1. Field of the Invention
The present invention relates to the separation of drilling/production fluids and drilled earthen solids drilled cuttings, such as drilled cuttings from downhole. More particularly, the present invention relates to a method of separating drilling/production fluids from the drilled cuttings whereby the drilled cuttings are carried by the drilling/production fluids from the drill bit through the annulus and received at the furthest exit point from the well bore for separation and treatment without having to be pre-conditioned through shale shakers, d-sanders, d-silters or other type treatment.
2. General Background of the Invention
Drilled cuttings are generated during the oil and gas drilling operations as the drill bit cuts the earthen formation and is carried by the drilling fluids to the surface of the well for disposition. Drilling fluids leaving the well bore containing drilled earthen solids (drilled cuttings) require separation from the carrier fluid for continuous re-use of the fluid during the drilling operations. Surface pumps are used to convey the drilling fluids down through the drill string (drill pipe) to maintain formation pressure, aid in the drilling process by adding hydraulic force to the drill bit, as well as prolonging the drill bits useful life span by lubrication of the bit and disbursing heat. Other uses for the drilling fluids would include, but not limited to, maintaining hydrostatic pressure, maintaining a wall cake of the formation surfaces for well bore stability, as well as being used as a medium to convey the drilled cuttings from the well bore to the surface of the well.
In the present state of the art, the manner in which the drilled cuttings are treated after reaching the surface is widely known in oil well drilling and production. Historically, when the drilled cuttings, carried by the drilling fluid reaches the surface of the well, the mixture of drilled cuttings and fluids enter a flow line directly off of the drilling or production string, where the mixture flows. The mixture may encounter a gumbo buster, or the like which is a device for diffusing very large solids from the mixture. Next the cuttings laden fluid is routed to a series of shale shakers, d-sanders and d-silters which enhances the separation of smaller solids further separate the drilled cuttings from the fluids of the mixture. The solids are then collected and discarded into the environment or containerized and returned for disposal, or further treatment before final disposition depending on environmental regulations in a specific area. Depending upon their content, the solids are moved into a decanting centrifuge, where the finer solids are removed from the fluids. If the oil content in the mixture is less than 6.9%, but not limited to, then the solids can be discarded to the environment, (which is a limitation dictated by the EPA,) and the fluids are routed back into the borehole for continued use in the drilling/production operations. This multi-stage process is a very expensive and tedious manner in which to efficiently separate the solids from the fluids. There is a need in the industry to simplify the process by eliminating certain steps and combining the treatment into a single confined treatment area to achieve final separation, and eliminate components in the process.